As is generally well known, when a towed trailer is not level relative to a towing vehicle or road surface, the load carried by such towed trailer may not remain secure. This condition can cause the trailer to make wide-angled turns, and possibly, jackknife, if traveling at a high enough speed. Not only would this condition be dangerous to the driver towing the load, but for other drivers and pedestrians as well. The problem is especially felt by the owners and operators of medium-sized trucks that are tasked with frequent coupling and uncoupling of trailers in order to tow various loads and/or equipment to and from job sites.
Prior to the conception and design of the present invention, efforts have been made to alleviate difficulties in trailer leveling. U.S. Pat. No. 6,908,094 issued to Sellers, U.S. Pat. No. 6,663,113 issued to Rosenlund, U.S. Pat. No. 6,575,488 issued to Massey, U.S. Pat. No. 5,975,553 issued to Van Vleet, U.S. Pat. No. 5,511,813 issued to Kravitz, U.S. Pat. No. 4,662,647 issued to Clavert and U.S. Pat. No. 3,400,949 issued to Kendall disclose various hitch coupling devices for adjusting the vertical position of the trailer hitch ball. However, it has been found that such prior art devices have greater than desirable complexity and are thus characterized by a greater than desirable cost. Furthermore, it has been found necessary to improve resistance of such hitch coupling devices to lateral movements during use.
Therefore, there is a need for an improved trailer hitch apparatus for connecting a hitch coupling of a towed vehicle at adjustable heights to a hitch coupling of a towing vehicle.